A study of the possible effect of abnormal patella height on meniscal tears

Anatomical and clinical significance of the Cyrano long-nosed patella in combination with patellofemoral instability: a case report and review of literature

BACKGROUND

The combination of a long-nosed patella and patella alta can lead to symptoms such as anterior knee pain and patellofemoral instability.

PURPOSE

Our objective was to address this uncommon, multifactorial cause of patellar pain and instability by a single-stage combined surgical approach.

CASE PRESENTATION

A 14-year-old German female presented to our hospital for recurrent patellar dislocations and exacerbated infrapatellar pain during kneeling. Following physical examination and imaging, the patient was diagnosed with patellar instability combined with the rare "Cyrano"-type patella. The patient underwent a single-stage procedure that included knee arthroscopic exploration, inferior pole osteotomy of the patella, tibial tuberosity osteotomy, and dynamic medial patellofemoral ligament reconstruction. Following the surgical procedure, the symptoms of knee pain and instability were entirely alleviated, accompanied by notable enhancements in the Knee Injury and Osteoarthritis Outcome Score , Kujala Score, and Lysholm Score. Notably, no recurrence was observed throughout the 2-year follow-up period.

CONCLUSION

The entity of a symptomatic Cyrano patella may be combined with patellofemoral instability. Osteotomy and surgical excision of the long-nosed aspect of the inferior pole, coupled with the realignment of the patellofemoral joint in both coronal and sagittal planes, alleviated pain and enhanced knee joint stability, ultimately contributing to the resolution of this uncommon condition. A sagittal plane deformity of the patellar shape may significantly affect the measurement of the patella height, as the Insall-Salvati index may not correctly determine the height of a patella owing to the elongated nose.

LEVEL OF EVIDENCE IV

Simultaneous reconstruction of a medial meniscus posterior root tear and medial patellofemoral ligament reconstruction with a synthetic graft

Patellar dislocations are common injuries, accounting for approximately 3% of all knee injuries. We present the case of an early 20s man who had sustained a traumatic patellar dislocation after a direct blow to the right knee. The dislocation was reduced, and MRI was conducted, which demonstrated concurrent posterior medial meniscal root (PMR) and medial patellofemoral ligament (MPFL) tear in the right knee. Following a repeat presentation of recurrent dislocation, the patient was surgically managed with arthroscopic simultaneous reconstruction of the PMR and the MPFL. This case demonstrated the importance of recognising the potential for concurrent soft tissue injuries with traumatic patellar dislocations and comprehensively assessing and managing these appropriately to avoid recurrent dislocations.

Abnormal patella height may be an independent risk factor in meniscal tears: a retrospective study in paediatric patients

PURPOSE

The literature on factors predisposing to meniscal tears in the paediatric population focuses on concomitant injuries such as anterior cruciate ligament rupture (ACL) or abnormal meniscus morphology such as discoid menisci. Patella alta has been associated with ACL ruptures but its association with meniscal tears has not been described. The purpose of our study was to evaluate whether abnormal patella height is associated with isolated meniscus tears in skeletally immature patients METHODS: We retrospectively analysed all patients under 16 years of age who had an isolated meniscal tear diagnosis confirmed on arthroscopic surgery. We examined data on demographics, meniscal morphology and patella height using the Insall-Salvati and Caton-Dechamp ratios. We compared the incidence of meniscal tears to a literature derived sex and age matched asymptomatic control group with normal patella heights.

RESULTS

A total of 39 patients with an isolated meniscal tear were identified (mean age 13.2years). Patella alta was present in 16 (41%). 21 had normal meniscus morphology, and 18 had a discoid meniscus. There was a significant association between patella alta and isolated meniscal tears compared to the control group (p = 0.001).

CONCLUSIONS

Our analysis is the first to demonstrate an association between abnormal patella height and the incidence of isolated meniscal tears in skeletally immature patients. Further research of knee biomechanics is required to elicit the mechanism and quantify the risk which may be used to guide prevention strategies and management of patients who wish to participate in high-risk sporting activities.

Evaluation of Anatomical Variations with Morphological Measurements and Their Relationship to Meniscal Injury and Ligament Damage

The purpose of this study was to reveal the anatomical risk factors for anterior and posterior cruciate ligament (ACL and PCL) injuries and menisci injury. We aim to investigate whether there are significant relationships between tibial tubercle-trochlear groove (TT-TG) distance, patella angle, trochlear sulcus angle (TSA), trochlear groove depth (TGD), medial and lateral trochlea length (MT and LT), MT/LT ratio, lateral patellar tilt angle (LPTA), patella-patellar tendon angle (P-PTA), quadriceps-patellar tendon angle (QPA), Insall-Salvati index (ISI), medial and lateral trochlear inclination (MTI and LTI) measurements and important common pathologies such as ACL, PCL, medial and lateral meniscal injuries (MM and LM), peripatellar fat pad edema, chondromalacia, and effusion. Thus, the mechanisms of injury will be better understood by revealing important anatomical variations for meniscus and ligament damage. Three hundred eighty patients with knee magnetic resonance imaging examination were included in this study. Our patients who underwent knee magnetic resonance imaging were divided into groups according to the presence of MM tear, LM tear, ACL tear, PCL tear, peripatellar fat pad edema, chondromalacia and effusion. TT-TG distance, patella angle, TSA, TGD, MT, LT, MT/LT ratio, LPTA, P-PTA, QPA, ISI, MTI, and LTI were measured. In patients with ACL tear, age, LT, ML/LT ratio, and QPA measurements were found to be significantly higher. There was no significant difference between the participants' LPTA value and the presence of ACL tear, MM and LM injury. MT and ML/LT ratio were found to be significantly lower in the group with MM tear (p <0.001). The TT-TG distance was found to be significantly lower in the group with LM tear. Increased age, LT, ML/LT ratio, and QPA are predisposed risk for ACL tear. Decreased MT and ML/LT ratio are among the risk factors for MM tear. The anatomical variations are associated with ligament and meniscal injury.

Can Anterior Knee Pain Be Explained by Patella Position After Infrapatellar Tibia Intramedullary Nailing?

OBJECTIVE

The objective of this study is to investigate the postoperative position of the patella and its relationship with anterior knee pain in patients operated with infrapatellar reamed tibia intramedullary nailing (IMN).

MATERIALS AND METHODS

 Patients who underwent tibia IMN between 2019 and 2022 and who had anterior knee pain in their postoperative follow-up at least two outpatient clinic controls with an interval of at least one month were examined. Patellar height indices (Insall-Salvati, Blackburne-Peel, Caton-Deschamps, and modified Insall-Salvati) and sagittal angulation (patella-patellar tendon angles) were measured on the lateral direct radiographs of the patients in semi-flexion. As a control group, measurements were made on the contralateral intact extremity radiographs of the same patients.

RESULTS

 There was no significant difference in patellar height indices between the fractured and intact sides in any of the patients (p = 0.588; p = 0.747; p = 0.446; p = 0.573, respectively). When the sagittal angulations were analyzed, a significant difference was found between the fractured and intact sides of the patients (p = 0.048), resulting in an approximate three-degree change.

CONCLUSION

 Patellar sagittal balance has been identified as one of the contributing factors to the development of anterior knee pain following reamed tibial IMN. Further biomechanical and comprehensive clinical studies are needed on this subject.

Patellar height changes after treatment of tibia plateau fractures: A radiological analysis

OBJECTIVES

To determine the impact of tibial plateau fractures on patellar height and the factors affecting this impact.

METHODS

A total of 40 patients treated for plateau fractures between 2017-2021 were evaluated in this retrospective prognostic study. The patient group consisted of lateral radiographs of the operated knees, whereas the control group consisted of lateral radiographs of the healthy sides of the same patients. Insall-Salvati, Caton-Deschamps, Blackburne-Peel, and modified Insall-Salvati indices were measured for both groups. In addition, Schaztker and Luo classifications, as well as the demographic profiles of the patients, were analyzed.

RESULTS

There was no significant difference between the groups in terms of patellar height indices (p>0.05). A significant relationship was found between the Insall-Salvati (p=0.046) and Blackburne-Pell (p=0.011) indices and Luo classification. Post hoc analyses revealed a significant relationship between the Insall-Salvati index and "One Column" fractures and between the Blackburne-Peel index and "Two Column" fractures.

CONCLUSION

Long-term functions of tibial plateau fractures should be evaluated not only with a painless range of motion but also with patellar height. It should be noted that the Luo classification, which evaluates the plateau 3-dimensionally, may be associated with changes in postoperative patellar height values.

Association between Patellofemoral Anatomy and Chondral Lesions of the Knee in Patellofemoral Instability

Chondral injury is a serious consequence of patellar dislocation and patellofemoral instability (PFI). There is limited data on the relationship between radiological features such as sulcus angle and patellar height to the presence, location, and severity of chondral lesions. The purpose of this study was to determine the association of anatomical variants in patellofemoral instability with injuries sustained due to patellar dislocation. A cohort of 101 patients who had four or more episodes of dislocation or instability undergoing isolated arthroscopy or arthroscopies at the time of corrective realignment surgery were identified. The prevalence of chondral, ligamentous, and meniscal injuries was determined and correlated to the sulcus angle, tibial tubercle trochlear groove distance, and patellar height on magnetic resonance imaging (MRI) scans. A total of 101 patients was identified. At arthroscopy, the patella demonstrated the highest incidence of chondral injury (68%) followed by the trochlear groove (40%). Lateral meniscal injuries were noted in 6% of patients, medial meniscal injuries in 2%, and anterior cruciate ligament (ACL) injury in 3%. Chondral injuries were graded using the Outerbridge criteria and there was a correlation between more severe chondral injuries and a greater tilt angle (p = 0.05). The occurrence of injury to the lateral meniscus was associated with a higher Insall-Salvati ratio (p = 0.05). More severe chondral injuries are seen in patients with a greater tilt angle.

The Dynamic Effect of Anterior Cruciate Ligament Deficiency on Patellar Height

BACKGROUND

The anterior tibial translation (ATT) in case of Anterior Cruciate Ligament (ACL) tear can lead to dynamic alterations of the extensor apparatus biomechanics. The aim of this study is to evaluate the dynamic effect of isolated ACL deficiency on patellar height. The hypothesis is that the ATT of ACL-insufficient knees dynamically reduces patellar height.

METHODS

Skeletally mature patients who underwent ACL reconstruction using hamstring graft between January and December 2018 were included in this study. The Posterior Tibial Slope (PTS), Caton-Deschamps (CDI), modified Insall-Salvati (MISI), and Blackburne-Peel (BPI) indices were calculated in standard lateral and TELOS X-rays. The mean of the measurements calculated between two observers was used to compare these parameters.

RESULTS

95 patients (M: 57; F: 38; 95 knees) were included in the study with a mean age of 31.8 years (16-56 years old). Significant patellar height reduction (CDI: 0.11 [- 0.32; 0.31]; MISI: 0.09 [- 0.66; 0.30]) was reported in TELOS compared with standard lateral knee radiography (p < 0.001). 20.0% of the study knees reported an abnormal CDI and 84.2% (16/19 knees) of them reduced this index to within normal limits in TELOS. 20.0% of the knees with mild patella alta reduced CDI in TELOS but always remained above 1.2.

CONCLUSIONS

The abnormal ATT in case of ACL-deficient knees results in a lowering effect of the patella in TELOS X-rays. In patients with ACL tear and anterior pain the reconstructive ligament surgery should be performed to avoid also chronic anterior knee pain.

LEVEL OF EVIDENCE

Basic Science Study (Case Series).

CLINICAL RELEVANCE

The decrease in patellar height in stress-X-rays compared with standard lateral knee radiography in ACL deficient knees, should be considered as a possible contributing cause of anterior pain in these patients.